$(a)$ What type of ores are calcined? Illustrate by giving a suitable example.
$(b)$ In what form is the calcined ore obtained,and how can it be reduced? Give chemical equations of the reduction process involved for the example provided by you.
$(c)$ Name two metals used as reducing agents by displacing metals of lower reactivity from their compounds.

(N/A) Carbonate ores are subjected to calcination.
Example: Zinc carbonate $(ZnCO_{3})$ is calcined to form zinc oxide $(ZnO)$.
$ZnCO_{3}(s) \xrightarrow{\text{Heat}} ZnO(s) + CO_{2}(g)$
$(b)$ The calcined ore is obtained in the form of a metal oxide. It can be reduced to the metal using a reducing agent like carbon (coke) or by electrolytic reduction.
For the example of zinc oxide $(ZnO)$:
$ZnO(s) + C(s) \rightarrow Zn(s) + CO(g)$
$(c)$ Two metals used as reducing agents are Aluminum $(Al)$ and Sodium $(Na)$.